How do I use the alternator check function?

To check the alternator, first ensure the battery is fully charged, then run the engine to achieve normal idle speed with all vehicle accessories turned off to verify no-load voltage. Next, load the alternator by turning on as many accessories as possible (except A/C and Defrost) and compare the readings. Note that this check only works for 12 volt systems and may not be accurate for every vehicle make, model, and manufacturer.